Image display device with pixel sections arrayed in a matrix

ABSTRACT

In an image display device where a lenticular lens, a display panel, and a light source are provided in order from a viewer side, when cylindrical lenses of the lenticular lens are arrayed in a horizontal direction, in first-viewpoint pixels and second-viewpoint pixels of the display panel, openings whose sides which intersect with straight lines in the horizontal direction are not parallel to a vertical direction are formed. And, a shape of the openings of a pair of pixels mutually adjacent in the vertical direction is made line-symmetric with respect to edges of the pixels extending in the horizontal direction as an axis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. Nos.13/102,274, filed on May 6, 2011, which is a Divisional of U.S. patentapplication Ser. No. 11/159,202, filed on Jun. 23, 2005, U.S. Pat. No.7,965,365 issued Jun. 21, 2011, which claims priority from JapanesePatent Application No. 2004-256569, filed on Sep. 3, 2004, the contentsof all of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image display device capable ofdisplaying different images at a plurality of viewpoints, a portableterminal equipped with the same, and a display panel and a lensincorporated in the image display device, and in particular, it relatesto an image display device capable of displaying a three-dimensionalimage with an excellent quality, a portable terminal, a display panel,and a lens.

2. Description of the Related Art

Priorly, image display devices capable of displaying different images ata plurality of viewpoints have been investigated. As an example thereof,a three-dimensional image display device on the premise of displayingparallax images as multi-viewpoint images exists. In B.C. 280, the Greekmathematician Euclid considered that “Three-dimensional imaging is asensation obtained when both right and left eyes simultaneously look atdifferent images of an identical object viewed from differentdirections” (see authored by Chihiro Masuda, “Three-DimensionalDisplay,” Sangyotosho Co., Ltd., for example.) Namely, by presentingimages with parallax to both right and left eyes, a three-dimensionalimage display device can be realized.

In order to concretely realize this function, numerous three-dimensionalimage display systems have been investigated so far, and these can beroughly divided into systems using eyeglasses and systems using noeyeglasses. Of these, the systems using eyeglasses include an anaglyphsystem, a polarizing eyeglass system utilizing polarization and thelike, however, with these systems, since the burden of wearingeyeglasses cannot be essentially avoided, no-eyeglass systems using noeyeglasses have been investigated in recent years. The no-eyeglasssystems include a parallax barrier system, a lenticular lens system andthe like.

First, description is given of the parallax barrier system. The parallaxbarrier system is a three-dimensional image display system conceived byBerthier in 1896 and verified by Ives in 1903. FIG. 1 is an opticalmodel diagram showing a method that displays three-dimensional image bya parallax barrier system. As shown in FIG. 1, a parallax barrier 105 isa barrier (shading plate) in which a large number of narrow-stripedopenings, namely, slits 105 a have been formed. In the vicinity of oneof the surfaces of this parallax barrier 105, a display panel 102 isarranged. In the display panel 102, right-eye pixels 123 and left-eyepixels 124 have been arrayed in a direction orthogonal to thelongitudinal direction of the slits 105 a. In addition, in the vicinityof the other surface of the parallax barrier 105, namely, on theopposite side of the display panel 102, a light source 108 is arranged.

Light emitted from the light source 108 is blocked in part by theparallax barrier 105. On the other hand, light that has passed throughthe slits 105 a without being blocked by the parallax barrier 105becomes light fluxes 181 through the right-eye pixels 123 or becomeslight fluxes 182 through the left-eye pixels 124. At this time, theposition of a viewer where recognition of a three-dimensional imagebecomes possible is determined based on a positional relationshipbetween the parallax barrier 105 and pixels. Namely, it is necessarythat a right eye 141 of a viewer 104 is within a passing-area of alllight fluxes 181 corresponding to a plurality of right-eye pixels 123,and also, a left eye 142 of the viewer is within a passing-area of alllight fluxes 182. This is a case where a middle point 143 between theviewer's right eye 141 and left eye 142 is positioned within aquadrangular three-dimensional visible area 107 shown in FIG. 1.

Of line segments extending in the array direction of the right-eyepixels 123 and left-eye pixels 124 in the three-dimensional visible area107, a line segment that passes through an intersection point 107 abetween diagonal lines of the three-dimensional visible area 107 is thelongest. Therefore, when the middle point 143 is positioned at theintersection point 107 a, since a tolerance when the viewer's positionis deviated in the left-and-right direction is maximized, this isoptimal as an viewing position. Accordingly, in this three-dimensionalimage display method, it is recommended to the viewer to set a distancebetween the intersection point 107 a and display panel 102 to an optimalview distance OD and view at the optimal view distance OD. Here, in thethree-dimensional visible area 107, a virtual plane having the optimalview distance OD as a distance from the display panel 102 is referred toas an optimal view plane 107 b. Thus, lights from the right-eye pixels123 and left-eye pixels 124 reach the viewer's right eye 141 and lefteye 142, respectively. Therefore, it becomes possible for the viewer torecognize images displayed on the display panel 102 as athree-dimensional image.

In the aforementioned parallax barrier system, since the parallaxbarrier had been initially arranged between the pixels and eyes whenthis was devised, this had obstructed the view and there had been aproblem of low visibility. However, with the recent realization ofliquid crystal display devices, as shown in FIG. 1, it has becomepossible to arrange the parallax barrier 105 behind the display panel102, whereby the problem of visibility has been improved. Therefore,three-dimensional image display devices with the parallax barrier systemhave been currently actively investigated, and three-dimensional imagedisplay devices to which the parallax barrier system has been appliedhave been actually commercialized (see Nikkei Electronics, Jan. 6, 2003,No. 838, p. 26-27.)

For example, in Table 1 of Nikkei Electronics, Jan. 6, 2003, No. 838, p26-27, a portable telephone equipped with a 3D-compatible liquid crystalpanel has been introduced. A liquid crystal display panel of athree-dimensional image display device of this portable telephone has a2.2-inch diagonal size and a display dot number of 176 dot wide×220 dothigh. And, a liquid crystal panel for a switch to turn on/off parallaxbarrier effects is provided, and this can display a three-dimensionaldisplay and a planar display by switching.

Next, description will be given of the lenticular lens system. Asdescribed in the aforementioned publication, authored by Chihiro Masuda,“Three-Dimensional Display,” Sangyotosho Co., Ltd., Ives et al. inventedthe lenticular lens system in around 1910. FIG. 2 is a perspective viewshowing a lenticular lens, and FIG. 3 is an optical model diagramshowing a method that displays three-dimensional image by a lenticularlens system. As shown in FIG. 2, a lenticular lens 121 has a flat planeon one of the surfaces, and on the other surface, semicylindricalconvexities (cylindrical lenses 122) extending in one direction havebeen formed in plurality so that their longitudinal directions becomemutually parallel.

And, as shown in FIG. 3, in the three-dimensional image display deviceby a lenticular lens system, a lenticular lens 121, a display panel 102,and a light source 108 are arranged in order from a viewer side, and ona focal plane of the lenticular lens 121, pixels of the display panel102 are positioned. In the display panel 102, pixels 123 to display animage for a right eye 141 and pixels 124 to display an image for a lefteye 142 are alternatively arrayed. At this time, groups each composed ofmutually adjacent pixels 123 and 124 are corresponding to the respectivecylindrical lenses (convexities) 122 of the lenticular lens 121.Thereby, when light which has been emitted from the light source 108 andhas passed through the respective pixels is sorted by the cylindricallenses 122 of the lenticular lens 121 in directions toward the right andleft eyes, it becomes possible to make the right and left eyes recognizemutually different images, thus the viewer can be made to recognize athree-dimensional image.

The aforementioned parallax barrier system is a system for “blocking” anunnecessary light by a barrier, whereas the lenticular lens system is asystem for changing light progressing directions, therefore, inprinciple, there is no decline in brightness of the display screen owingto provision of a lenticular lens. Therefore, in particular, applicationto portable apparatuses and the like where a high-luminance display andlow-power-consumption performance are regarded as important has beenconsidered dominant.

An example of a three-dimensional image display device developed by thelenticular lens system has been described in the aforementioned NikkeiElectronics, Jan. 6, 2003, No. 838, p. 26-27. A liquid crystal displaypanel of a three-dimensional image display device of this portabletelephone has a 7-inch diagonal size and a display dot number of 800 dotwide×480 dot high. And, by changing the distance between the lenticularlens and liquid crystal display panel by 0.6 mm, switching between athree-dimensional display and a planar display can be made. Thisthree-dimensional image display device has a horizontal viewpoint numberof five, and five different images can be viewed by changing angles inthe horizontal direction.

In addition, as an another example of an image display device capable ofdisplaying different images at a plurality of viewpoints, a display farsimultaneously displaying multiple images has been disclosed (seeJapanese Published Unexamined Patent Application No. 332354/1994). Thedisplay as set forth in Japanese Published Unexamined Patent ApplicationNo. 332354/1994 simultaneously displays different planar images in eachof the viewing directions by utilizing an image sorting function by alenticular lens, whereby making it possible for a plurality of differentviewers to simultaneously observe, on a single display, different planarimages from different directions, respectively. FIG. 4 is a perspectiveview showing this display for simultaneously displaying multiple images.As shown in FIG. 4, in this display for simultaneously displayingmultiple images, a lenticular lens 121 and a display panel 102 arearranged in order from a viewer 104 side. In the display panel 102,first-viewpoint pixels 125 to display an image for a first viewpoint andsecond-viewpoint pixels 126 to display an image for a second viewpointare alternatively arrayed. At this time, groups each composed ofmutually adjacent pixels 125 and 126 are corresponding to respectivecylindrical lenses (convexities) 122 of the lenticular lens 121.Thereby, since lights from the respective pixels are sorted intodifferent directions by the cylindrical lenses 122 of the lenticularlens 121, it becomes possible to recognize different images at differentpositions. By using this display for simultaneously displaying multipleimages, in comparison with a case where displays for the number ofpeople are prepared, installing space and electricity expenses and thelike can be reduced. As such, currently, image display devices that candisplay different images at a plurality of viewpoints have been activelyinvestigated.

However, the aforementioned prior arts have the following problems.Namely, in display panels used for image display devices, a shadingportion is provided between the pixels for respective viewpoints. Sincethis shading portion has no display function, non-display areas where nodisplay is carried out are formed between images for respectiveviewpoints. When a viewer had shifted his/her view position from imagesfor respective viewpoints, he/she is to view non-display areas, however,since no display is carried out in the non-display areas as mentionedabove, the viewer cannot view an image. Moreover, generally, it isimprobable that a viewer views only at an optimal view position, and ashift in the view position can frequently occur. As a result, the vieweris conscious of a situation where viewing an image is impossible. Sinceno such situation occurs in an ordinal image display device having nooptical components for image sorting, the viewer senses that, in animage display device which can display different images at a pluralityof viewpoints, display quality is considerably deteriorated incomparison with the ordinal image display device.

Hereinafter, this problem will be described in detail by raising anexample of a three-dimensional image display device by a lenticular lenssystem using a display panel whose pixel opening ratio in an arraydirection (horizontal direction) of cylindrical lenses is 50%. FIG. 5 isa plan view showing a conventional display panel whose pixel openingratio in a horizontal direction is 50%, and FIG. 6 is an optical modeldiagram of a three-dimensional image display device by a lenticular lenssystem using the display panel shown in FIG. 5. As shown in FIG. 5,since this display panel 102 has a pixel pitch of P and a pixel openingratio of 50% in a lens array direction (horizontal direction 112),openings 109 whose width is (P/2) are formed at the centers of pixels.Namely, a width of a shading portion 106 in the horizontal direction 112of each pixel is (P/4). In addition, as shown in FIG. 6, in thethree-dimensional image display device using this display panel 102, alenticular lens 121, the display panel 102, and a light source 108 arearranged in order from a viewer side, and pixels of the display panel102 are positioned at a focal plane of the lenticular lens 121. And, adistance between an apex of the lenticular lens 121 and pixels of thedisplay panel 102 is provided as H, a refractive index of the lenticularlens 121 is provided as n, a focal distance is provided as f, and a lenspitch is provided as L. In addition, in display pixels of the displaypanel 102, sets of one each of left-eye pixels 124 and right-eye pixels123 are arranged, and a pitch of each pixel is provided as P.Accordingly, a display pixel composed of one each of left-eye pixels 124and right-eye pixels 123 has an array pitch of 2P. To this display pixelcomposed of two pixels of one each of left-eye pixels 124 and right-eyepixels 123, one cylindrical lens 122 is arranged in a correspondingmanner.

In addition, a distance between the lenticular lens 121 and viewer isprovided as an view distance OD, enlarged projection widths of pixels atthis view distance OD, that is, widths of projection images of theleft-eye pixel 124 and right-eye pixel 123 on a virtual plane which isdistant from the lens by the view distance OD and is parallel to thelens are provided as e, respectively. Furthermore, a distance from thecenter of a cylindrical lens 122 positioned at the middle of thelenticular lens 121 to the center of a cylindrical lens 122 at the endof the lenticular lens 121 in the horizontal direction 112 is providedas W_(L), and a distance between the center of a display pixel composedof a left-eye pixel 124 and a right-eye pixel 123 positioned at thecenter of the display panel 102 and center of a display pixel positionedat the end of the display panel 102 in the lens array direction 112 isprovided as W_(P). Still furthermore, incident angles and exit angles oflight at a cylindrical lens 122 positioned at the middle of thelenticular lens 121 are provided as α and β, respectively, and incidentangles and exit angles of light at a cylindrical lens 122 positioned atthe end of the lenticular lens 121 in the lens array direction 112 areprovided as γ and δ, respectively. Still furthermore, a differencebetween the distance W_(L) and distance W_(P) is provided as C, and anumber of pixels contained in a area at the distance W_(P) is providedas 2m.

Since the array pitch L of the cylindrical lenses 122 and the arraypitch P of the pixels are mutually related, one is to be determined inaccordance with the other, however, usually, since a lenticular lens isdesigned in accordance with a display panel in most cases, the arraypitch P of pixels is treated as a constant. In addition, the refractiveindex n is determined by selecting a material of the lenticular lens121. In contrast thereto, for the view distance OD between the lens andviewer and enlarged projection widths e of pixels in this view distanceOD, desirable values are set. By use of these values, the distance Hbetween the lens apex and pixels and the lens pitch L are determined. BySnell's law and geometric relationships, the following expressions 1through 6 hold true.n×sin α=sin β  (Expression 1)OD×tan β=e  (Expression 2)H×tan α=P  (Expression 3)n×sin γ=sin δ  (Expression 4)H×tan γ=C  (Expression 5)OD×tan δ=W _(L)  (Expression 6)

In addition, the following expressions 7 through 9 hold true.W _(P) −W _(L) =C  (Expression 7)W _(P)=2×m×P  (Expression 8)W _(L) =m×L  (Expression 9)

And, based on the above-described expressions 1 through 3, the followingexpressions 10 through 12 hold true, respectively.β=arctan(e/OD)  (Expression 10)α=arcsin(1/n×sin β)  (Expression 11)H=(P/tan α)  (Expression 12)

In addition, based on the above-described expressions 6 through 9, thefollowing expression 13 holds true.δ=arctan(m×L/OD)  (Expression 13)

Furthermore, based on the above-described expressions 7 and 8, thefollowing expression 14 holds true.C=2×m×P−m×L  (Expression 14)

Still furthermore, based on the above-described expression 5, thefollowing expression 15 holds true.γ=arctan(C/H)  (Expression 15)

Here, as mentioned above, since the distance H between the lenticularlens apex and pixels is usually made equal to the focal distance f ofthe lenticular lens, the following expression 16 holds true, and where aradius of curvature of the lens is provided as r, the radius ofcurvature r is obtained by the following expression 17.f=H  (Expression 16)r=H×(n−1)/n  (Expression 17)

As shown in FIG. 6, a area where lights from all right-eye pixels 123reach is provided as a right-eye area 171, and a area where lights fromall left-eye pixels 124 reach is provided as a left-eye area 172. Aviewer can recognize a three-dimensional image by positioning his/herright eye 141 at the right-eye area 171 and positioning his/her left eye142 at the left-eye area 172. However, non-display areas 173 existbetween the right-eye area 171 and left-eye area 172. For investigatingthe size of these non-display areas 173, where an incident angle andexit angle of a light beam which is emitted from the left end of anopenings of a right-eye pixel of the display panel 102 and passesthrough the cylindrical lens 122 positioned at the middle of thelenticular lens 121 are provided as α₁ and β₁, respectively, a distancee₁ from a centerline to an enlarged projection position of acenterline-side shading portion at the optimal view distance OD isobtained by the following expressions 18 through 20.n×sin α₁=sin β₁  (Expression 18)OD×tan β₁ =e ₁  (Expression 19)H×tan α₁ =P/4  (Expression 20)

Similarly, where an incident angle and exit angle of a light beam whichis emitted from the right end of an opening and passes through thecylindrical lens 122 positioned at the middle of the lenticular lens 121are provided as α₂ and β₂, respectively, a distance e2 from a centerlineto an enlarged projection position of an end-side shading portion at theoptimal view distance OD is obtained by the following expressions 21through 23.n×sin α₂=sin β₂  (Expression 21)OD×tan β₂ =e ₂  (Expression 22)H×tan α₂=3×P/4  (Expression 23)

As an example, where polymethyl-methacrylate (PMMA) whose refractiveindex n is 1.49 is used as a material of the lenticular lens 121, and apixel pitch is provided as 0.24 mm, an optimal view distance OD isprovided as 280 mm, an enlarged projection width of pixels as 65 mm, andthe number m of display pixels is provided as 60, based on theaforementioned respective expressions, the distance H between the lensplane and pixels becomes 1.57 mm, the focal distance f of the lensbecomes 1.57 mm, the lens pitch L becomes 0.4782 mm, and the radius ofcurvature r of the lens becomes 0.5161 mm. In addition, the distance e₁to an enlarged projection position of a shading portion becomes 16 mm,and e₂ becomes 49 mm. These results show that, when the pixel openingratio in the horizontal direction 112 is 50%, the width of thenon-display area on the view plane also becomes 50%. Accordingly, when aviewer is positioned at the non-display area, since the viewer cannotrecognize an image, he/she senses that the display quality has beenconsiderably deteriorated.

Similar problems occur in three-dimensional image display devices notonly by lens systems but also by parallax barrier systems. Hereinafter,a problem of non-display area in the parallax barrier system will bedescribed in detail. FIG. 7 is an optical model diagram showing athree-dimensional image display device by a conventional parallaxbarrier system wherein a parallax barrier has been provided at aviewer's side. First, description is given of the sizes of respectiveportions of a three-dimensional image display device provided with aparallax barrier in which ordinal slit-like opening have been formed anda display panel. Here, for the convenience of description, a slit widthof the parallax barrier is considered as being extremely small anddisregardable. In addition, the slits in the parallax barrier aresupposed to be arrayed in the horizontal direction in large numbers. Asshown in FIG. 7, an array pitch of slits 105 a in a parallax barrier 105is provided as L, and a distance between the display panel 102 andparallax barrier 105 is provided as H. In addition, an array pitch ofpixels is provided as P. As mentioned above, in the display panel 102,since display pixels are arranged as sets of two pixels, that is, oneeach of right-eye pixels 123 and left-eye pixels 124, an array pitchthereof becomes 2P. Since the array pitch L of the slits 105 a and thearray pitch P of the display pixels are mutually related, one is to bedetermined in accordance with the other, however, usually, since aparallax barrier is designed in accordance with a display panel in mostcases, the array pitch P of pixels is treated as a constant.

In addition, a area where lights from all right-eye pixels 123 reach isprovided as a right-eye area 171, and a area where lights from allleft-eye pixels 124 reach is provided as a left-eye area 172. A viewercan recognize a three-dimensional image by positioning his/her right eye141 at the right-eye area 171 and positioning his/her left eye 142 atthe left-eye area 172. A distance from the display panel 102 to theviewer is provided as an optimal view distance OD. Furthermore, anenlarged projection width of one pixel on the view plane at the optimalview distance OD is provided as e.

Next, by use of the foregoing respective values, the distance H betweenthe parallax barrier 105 and pixels of the display panel 102 isdetermined. By the geometric relationships shown in FIG. 7, thefollowing expression 24 holds true, thereby, as shown in the followingexpression 25, the distance H is obtained.P:H=e:(OD−H)  (Expression 24)H=OD×P/(P+e)  (Expression 25)

Furthermore, where a distance between the center of a display pixelpositioned at the center in a horizontal direction 112 of the displaypanel 102 and center of a display pixel positioned at the end in thehorizontal direction 112 is provided as W_(P), and a distance betweenthe centers of slits 105 a corresponding to these display pixels,respectively, is provided as W_(L), a difference C between the distanceW_(P) and distance W_(L) is given by the following expressions 26.W _(P) −W _(L) =C  (Expression 26)

In addition, in the display panel 102, where a number of pixelscontained at the distance W_(P) is provided as 2m, the followingexpressions 27 and 28 hold true.W _(P)=2×m×P  (Expression 27)W _(L) =m×L  (Expression 28)

Furthermore, since the following expression 29 holds true based on thegeometric relationships, the pitch L of the slits 105 a in the parallaxbarrier 105 is given by the following expression 30.W _(P) :OD=W _(L):(OD−H)  (Expression 29)L=2×P×(OD−H)/OD  (Expression 30)

When the opening ratio of the pixels is 50%, a distance e₁ from acenterline to an enlarged projection position of a centerline-sideshading portion at the optimal view distance OD can be obtained by thefollowing expression 31 using the above-described expression 24, sincethis is a position of a light beam emitted from the left end of anopening of the right-eye pixel 123 of the display panel 102 on an viewplane at the optimal view distance OD.e ₁=(P/4)×(OD−H)/H  (Expression 31)

Similarly, a distance e₂ from a centerline to an enlarged projectionposition of an end-side shading portion at the view distance OD can beobtained by the following expression 32, since this is a position of alight beam emitted from the right end of an opening of the right-eyepixel 123 of the display panel 102 on an view plane at the optimal viewdistance OD.e ₂=(3×P/4)×(OD−H)/H  (Expression 32)

Since the above-described expressions 31 and 32 indicate that when theopening ratio in the barrier array direction is 50%, the width of thenon-display area on the view plane also becomes 50%. When a viewer ispositioned at the non-display area, the viewer cannot recognize animage; he/she senses that display quality has been considerablydeteriorated.

Furthermore, a similar problem occurs in a three-dimensional imagedisplay device provided with a parallax barrier in the rear of a displaypanel, as well. Hereinafter, this problem will be described in detail.FIG. 8 is an optical model diagram showing a three-dimensional imagedisplay device by a conventional parallax barrier system wherein aparallax barrier has been provided in the rear of a display panel.First, description is given of the sizes of respective portions of athree-dimensional image display device provided with a parallax barrierin which ordinal slit-like openings have been formed and a displaypanel. Here, for the convenience of description, a slit width of theparallax barrier is considered as being extremely small anddisregardable. In addition, the slits in the parallax barrier aresupposed to be arrayed in the horizontal direction in large numbers. Asshown in FIG. 8, an array pitch of slits 105 a in a parallax barrier 105is provided as L, and a distance between the display panel 102 andparallax barrier 105 is provided as H, in a similar fashion as the casewhere the parallax barrier 105 is arranged in the front of theabove-described display panel 102. In addition, an array pitch of pixelsis provided as P. As mentioned above, in the display panel 102, sincedisplay pixels are arranged as sets of two pixels, that is, one each ofright-eye pixels 123 and left-eye pixels 124, an array pitch thereofbecomes 2P. Since the array pitch L of the slits 105 a and the arraypitch P of the display pixels are mutually related, one is to bedetermined in accordance with the other, however, usually, since aparallax barrier is designed in accordance with a display panel in mostcases, the array pitch P of pixels is treated as a constant.

In addition, a area where lights from all right-eye pixels 123 reach isprovided as a right-eye area 171, and a area where lights from allleft-eye pixels 124 reach is provided as a left-eye area 172. A viewercan recognize a three-dimensional image by positioning his/her right eye141 at the right-eye area 171 and positioning his/her left eye 142 atthe left-eye area 172. A distance from the display panel 102 to theviewer is provided as an optimal view distance OD. Furthermore, anenlarged projection width of one pixel on the view plane at the optimalview distance OD is provided as e.

Next, by use of the foregoing respective values, the distance H betweenthe parallax barrier 105 and pixels of the display panel 102 isdetermined. By the geometric relationships shown in FIG. 8, thefollowing expression 33 holds true, thereby, as shown in the followingexpression 34, the distance H is obtained.P:H=e:(OD+H)  (Expression 33)H=OD×P/(e−P)  (Expression 34)

Furthermore, where a distance between the center of a display pixelpositioned at the center in a horizontal direction 112 of the displaypanel 102 and center of a display pixel positioned at the end in thehorizontal direction 112 is provided as W_(P), and a distance betweenthe centers of slits 105 a corresponding to these display pixels,respectively, is provided as W_(L), a difference C between the distanceW_(P) and distance W_(L) is given by the following expressions 35.W _(L) −W _(P) =C  (Expression 35)

In addition, in the display panel 102, where a number of pixelscontained at the distance W_(P) is provided as 2m, the followingexpressions 36 and 37 hold true.W _(P)=2×m×P  (Expression 36)W _(L) =m×L  (Expression 37)

Furthermore, since the following expression 38 holds true based on thegeometric relationships, the pitch L of the slits 105 a in the parallaxbarrier 105 is given by the following expression 39.W _(P) :OD=W _(L):(OD+H)  (Expression 38)L=2×P×(OD+H)/OD  (Expression 39)

When the opening ratio of the pixels is 50%, a distance e₁ from acenterline to an enlarged projection position of a centerline-sideshading portion at the optimal view distance OD can be obtained by thefollowing expression 40 using the above-described expression 33, sincethis is a position of a light beam emitted from the left end of anopening portion of the right-eye pixel 123 of the display panel 102 onan view plane at the optimal view distance OD.e ₁=(P/4)×(OD+H)/H  (Expression 40)

Similarly, a distance e₂ from a centerline to an enlarged projectionposition of an end-side shading portion at the optimal view distance ODcan be obtained by the following expression 41, since this is a positionof a light beam emitted from the right end of an opening of theright-eye pixel 123 of the display panel 102 on an view plane at theoptimal view distance OD.e ₂=(3×P/4)×(OD+H)/H  (Expression 41)

Since the above-described expressions 40 and 41 indicate that when theopening ratio in the barrier array direction is 50%, the width of thenon-display areas on the view plane also becomes 50%. When a viewer ispositioned at the non-display area, the viewer cannot recognize animage; he/she senses that display quality has been considerablydeteriorated.

Although a description has been given of a deterioration in displayquality caused by a shading portion of a display panel while raising theexamples of conventional three-dimensional image display devices, thisproblem is not limited to the three-dimensional image display devicesand can similarly occur in image display devices as long as these areprovided with optical components such as lenticular lenses and parallaxbarriers and the like.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an image displaydevice capable of preventing deterioration in display quality caused byshading portions of a display panel, a portable terminal device equippedwith the same, and a display panel incorporated in the image displaydevice.

An image display device according to the present invention comprises: adisplay panel which has a plurality of pixel sections each of whichincludes n (n is a natural number equal to or more than two) types ofpixels to display images for n viewpoints, the pixel sections beingarrayed in a matrix in a first direction and in a second directionorthogonal to the first direction; an optical unit for sorting lightsemitted from pixels arrayed in the first direction into mutuallydifferent directions along the first direction; and wherein displayareas are provided in each of the pixels, and a display area provided ineach of the pixels, in which at least two middle points between bothends of the display area in the first direction has different distancesfrom an optical axes of the optical unit, the middle points being apartfrom each other along the optical axes.

In the present invention, since at least two middle points between bothends of the display area in the first direction has different distancesfrom an optical axes of the optical unit, occurrence of non-display areawhere no light reaches from pixels can be suppressed. Thereby,deterioration in display quality caused by a shading portion can besuppressed.

In the pixels, the optical axes can be made parallel to the seconddirection. Thereby, since the position of middle point between both endsof the display area in the first direction varies depending on theposition in the second direction where the optical unit has no functionto emit light emitted from the pixels into mutually differentdirections, deterioration in display quality caused by a shading portioncan be suppressed.

It is preferable that each display area in a plurality of the pixelsarrayed along the second direction intersects with one straight lineextending in the second direction. In addition, the display area may bequadrangular, and directions in which sides of these display area whichintersect with straight lines extending in the first direction may notbe parallel to the second direction. Thereby, since occurrence ofnon-display area where no light reaches from pixels can be suppressed,deterioration in display quality caused by a shading portion can besuppressed. In this case, sides of each display area in pixels mutuallyadjacent in the second direction which intersect with straight linesextending in the first direction are tilted in, for example, mutuallyopposite directions with respect to the second direction, and angleswhich are created between directions in which these sides extend and thesecond direction are identical in size. Thereby, since an arraydirection of the pixels can be made identical to the second direction,deterioration in display quality that occurs as a result of an arraydirection of pixels being different from the second direction can beprevented.

Alternatively, sides of the display area that intersect with straightlines extending in the first direction are composed of straight linesparallel to the second direction and straight lines vertical to thesecond direction. Thereby, each opening area of the pixel present on anidentical straight line extending in the second direction can beenlarged, and illuminance at the boundary between respective viewpointimages can be improved, therefore, deterioration in display qualitycaused by a shading portion can further be suppressed.

Alternatively, sides of the display area, which intersect with straightlines extending in said first direction, are composed of curved lines.Thereby, since distribution of brightness on a view plane can be madeinto an arbitrary shape, setting with a higher degree of freedomaccording to desirable optical characteristics becomes possible. Inaddition, since the number of corners of a display area of the pixel canbe minimized to four, and also, all corners can be composed of rightangles, a decline in the opening ratio caused by the manufacturingmethod can be suppressed.

Furthermore, it is preferable that a shape of each display area in apair of pixels mutually adjacent in the second direction isline-symmetric with respect to edges of the pixels extending in thefirst direction as an axis. Thereby, since an array direction of thepixels can be made identical to the second direction, deterioration indisplay quality caused by a difference between the array direction ofthe pixels and second direction can be prevented.

Still furthermore, it is also possible to provide a plurality of displayareas in each pixel. Thereby, storage capacitance provided for each ofthe pixels and wiring to connect the storage capacitance can be arrangedbetween the respective display areas. In this case, the display panelcan be provided as a liquid crystal display panel, which can be operatedin an In-Plane Switching mode. When the liquid crystal display panel isoperated in an In-Plane Switching mode, deterioration in display qualitycaused by comb electrodes arranged to produce horizontal electric fieldscan be suppressed.

Still furthermore, it is preferable that a distance between both ends inthe second direction of the display areas is fixed irrespective of theposition in the first direction. Thereby, distribution of brightnesswith respect to the viewing position can be fixed, thus deterioration indisplay quality caused by a shading portion can be completelysuppressed.

Still furthermore, wiring may be provided between display areas of apair of pixels mutually adjacent in the first direction, and position ofa middle point between both ends in the first direction of the wiringmay vary in the first direction depending on the position in the seconddirection. Thereby, since an overlapping margin between the wiring andshading portion during assembly can be increased, the yield inmanufacturing can be improved.

Still furthermore, when the image display device is a three-dimensionalimage display device, the first direction is, for example, a horizontaldirection. Thereby, since images for a plurality of viewpoints arearranged in a viewer's horizontal direction, when parallax images aredisplayed as images for a plurality of viewpoints, an excellentthree-dimensional image display can be realized.

Alternatively, when the image display device is a planar image displaydevice, the first direction is, for example, a vertical direction.Thereby, viewer can view images for a plurality of viewpoints by onlychanging angles of the portable terminal device. In particular, whenimages for a plurality of viewpoints have a relationship to each other,since the respective images can be compared by a simple method ofchanging viewing angles, convenience is greatly improved. In addition,since images for a plurality of viewpoints are arrayed in the verticaldirection, the viewer can always view the images for the respectiveviewpoints with both eyes; therefore, visibility of images for therespective viewpoints can be improved.

In the image display device of the present invention, the optical unitsmay be a lenticular lens. Thereby, no such black striped pattern causedby a barrier as in a case where a parallax barrier is used occurs, thuslight loss is also reduced.

Alternatively, in the image display device of the present invention, theoptical unit may be a parallax barrier. Thereby, deterioration inquality of a display image owing to a lens pattern occurs less than thatin the case where a lenticular lens is used.

Alternatively, in the image display device of the present invention, theoptical unit may be a lenticular lens, and directions in which opticalaxes of cylindrical lenses of this lenticular lens extend may varydepending on a direction orthogonal to a direction in which thecylindrical lenses are arrayed. Thereby, deterioration in displayquality caused by a shading portion can be suppressed.

Another image display device according to the present inventioncomprises: a display panel which has a plurality of pixel sections eachof which includes n (n is a natural number equal to or more than two)types of pixels to display images for n viewpoints, the pixel sectionsbeing arrayed in a matrix in a first direction and in a second directionorthogonal to the first direction; an optical unit for sorting lightsemitted from pixels arrayed in the first direction into mutuallydifferent directions along the first direction; and a display areaprovided in each of the pixels, in which provided an area where aposition of an end of the display area in the first direction variesdepending on a position in the second direction.

In the present invention, since an area where a position of an end ofthe display area in the first direction varies depending on a positionin the second direction is provided in the display area, occurrence ofnon-display area where no light reaches from pixels can be suppressed.Thereby, deterioration in display quality caused by the shading portioncan be suppressed.

In this image display device, the position of middle point between bothends of the display area in the first direction and a position of anoptical axes of the optical unit can be made relatively invariable inthe second direction. In addition, the display areas may be polygonal,and of sides of these display area that intersect with straight linesextending in the first direction, at least one side may not be parallelto the second direction. Furthermore, the display area can each have apair of sides which intersect with straight lines extending in the firstdirection, whose extending directions are tilted in mutually oppositedirections with respect to the second direction, and angles createdbetween whose extending directions and second direction are identical insize. Still furthermore, the display area may have shapes includingtrapezoids. Thereby, deterioration in display quality caused by ashading portion can be suppressed.

For the image display device of the present invention, each display areaof the pixels mutually adjacent in the second direction can be madeline-symmetric with respect to edges of the pixels extending in thefirst direction as an axis, and each display area of the pixels mutuallyadjacent in the first direction can be made point-symmetric with respectto a middle point between intersection points between a line segmentjoining middle points between both ends in the second direction and aline segment joining middle points between both ends portion in thefirst direction. In addition, a sum of intervals between both ends inthe second direction of respective pixels mutually adjacent in the firstdirection may be fixed irrespective of the position in the firstdirection. Thereby, since distribution of brightness with respect toviewing position can be fixed, deterioration in display quality causedby a shading portion can be completely eliminated.

In addition, the display panel may have a first substrate on whichwiring has been formed and a second substrate which is arranged so as tobe opposed to this first substrate and on which a shading portion hasbeen formed, and the shading portion may not be formed between eachdisplay area of the pixels mutually adjacent in the first direction.Thereby, since a positional error margin in the first direction can beset great, it becomes possible to realize a high opening ratio.

Furthermore, the display panel has a color filter where an identicalcolor has been successively arranged along the first direction andrespective colors have been arranged in stripes along the seconddirection may be provided. Thereby, since it becomes unnecessary toshade same-color areas of the color filter, it becomes easy tomanufacture a color filter, and a reduction in cost can be realized.

Still furthermore, when the image display device is a three-dimensionalimage display device, the first direction is, for example, a horizontaldirection. Thereby, since images for a plurality of viewpoints arearranged in a viewer's horizontal direction, when parallax images aredisplayed as images for a plurality of viewpoints, an excellentthree-dimensional image display can be realized.

Alternatively, when the image display device is a planar image displaydevice, the first direction is, for example, a vertical direction.Thereby, a viewer can view images for a plurality of viewpoints by onlychanging angles of the portable terminal device. In particular, whenimages for a plurality of viewpoints have a relationship to each other,since the respective images can be compared by a simple method ofchanging viewing angles, convenience is greatly improved. In addition,since the images for a plurality of viewpoints are arrayed in thevertical direction, the viewer can always view images for the respectiveviewpoints with both eyes, therefore, visibility of images for therespective viewpoints can be improved.

In the image display device of the present invention, the optical unitmay be a lenticular lens. Thereby, no such black striped pattern causedby a barrier as in a case where a parallax barrier is used occurs, thuslight loss is also reduced.

Alternatively, in the image display device of the present invention, theoptical unit may be a parallax barrier. Thereby, deterioration inquality of a display image owing to a lens pattern occurs less than thatin the case where a lenticular lens is used.

Another image display device according to the present inventioncomprises: a liquid crystal display panel which has a plurality of pixelsections each of which includes n (n is a natural number equal to ormore than two) types of pixels to display images for n viewpoints, thepixel sections being arrayed in a matrix in a first direction and in asecond direction orthogonal to the first direction, and which operatesin a multi-domained vertical orientation mode; an optical unit forsorting lights emitted from pixels arrayed in said first direction intomutually different directions along the first direction; and a pluralityof display areas provided in each of the pixels, where a position ofmiddle points between both ends in the first direction varies dependingon a position in the second direction.

In the present invention, since a liquid crystal panel where a pluralityof display areas where positions of middle points between both endportions in the first direction vary depending on the position in thesecond direction are provided in each pixel is operated in amulti-domained vertical orientation mode, deterioration in displayquality caused by domain boundary areas which do not sufficientlypenetrate light can be suppressed.

A portable terminal device according to the present invention comprisesthe aforementioned image display devices. In addition, this portableterminal device is, for example, a portable telephone, Personal DigitalAssistant, a game machine, a digital camera, or a digital video camera.

A display panel according to the present invention comprises: aplurality of pixel sections arrayed in a matrix in a first direction andin a second direction orthogonal to the first direction, each of whichincludes n (n is a natural number equal to or more than two) types ofpixels to display images for n viewpoints; and a display area providedin each pixel, where a position of middle points between both ends inthe first direction varies depending on a position in the seconddirection.

It is preferable that each display area in a plurality of the pixelsarrayed in the second direction intersects with one straight lineextending in the second direction. In addition, the display area may bequadrangular, and directions in which sides of the display area whichintersect with straight lines extending in the first direction may notbe parallel to the second direction. In this case, sides of each displayarea in pixels mutually adjacent in the second direction which intersectwith straight lines extending in the first direction are tilted in, forexample, mutually opposite directions with respect to the seconddirection, and angles which are created between directions in whichthese sides extend and the second direction are identical in size.

Alternatively, sides of the display area that intersect with straightlines extending in the first direction may be composed of straight linesparallel to the second direction and straight lines vertical to thesecond direction. Alternatively, sides of the display area thatintersect with straight lines extending in the first direction may becomposed of curved lines.

In addition, it is preferable that a shape of each display area in apair of pixels mutually adjacent in the second direction isline-symmetric with respect to edges of the pixels extending in thefirst direction as an axis. Furthermore, a plurality of display areasmay be provided in each pixel, and in this case, it is preferable thatthe display panel is a liquid crystal panel that operates in an In-Planeswitching mode. Still furthermore, an interval between both ends in thesecond direction of the display area may be fixed irrespective of theposition in the first direction. Still furthermore, wiring may beprovided between display areas of a pair of pixels mutually adjacent inthe first direction, and position of a middle point between both ends inthe first direction of the wiring varies in, for example, the firstdirection depending on the position in the second direction. A displaypanel of the present invention can be incorporated into an image displaydevice, and by providing the first direction as a lens array directionof a lenticular lens of the image display device or a slit arraydirection of a parallax barrier, deterioration in display quality causedby a shading portion of the display panel can be prevented.

Another display panel according to the present invention comprises: aplurality of pixel sections arrayed in a matrix in a first direction andin a second direction orthogonal to the first direction, each of whichincludes n (n is a natural number equal to or more than two) types ofpixels to display images for n viewpoints; and a display area providedin each pixel, where a position of middle point between both ends in thefirst direction is invariable irrespective of a position in the seconddirection, and also a position of end in the first direction variesdepending on a position in the second direction.

The display area may be polygonal, and in this case, it is preferablethat, at least one side of said display area, which intersect withstraight lines extending in said first direction, is not parallel tosaid second direction. In addition, in the display area, a pair of sideswhich intersect with straight lines extending in the first direction,whose extending directions are tilted in mutually opposite directionswith respect to the second direction, and angles created between whoseextending directions and second direction are identical in size may beprovided. Furthermore, the display areas have shapes includingtrapezoids, for example.

Still furthermore, each display area of the pixels mutually adjacent inthe second direction may be line-symmetric with respect to edges of thepixels extending in the first direction as an axis, and each displayarea of the pixels mutually adjacent in the first direction may bepoint-symmetric with respect to a middle point between intersectionpoint between a line segment joining middle points between both ends inthe second direction and a line segment joining middle points betweenboth ends in the first direction. Still furthermore, a sum of intervalsbetween both ends in the second direction of respective pixels mutuallyadjacent in the first direction can be fixed irrespective of theposition in the first direction. Here, it is unnecessary that the sum ofintervals between both ends is strictly fixed, and it may beapproximately fixed.

This display panel may have a first substrate on which wiring has beenformed and a second substrate which is arranged so as to be opposed tothis first substrate and on which a shading portion has been formed, andin this case, it is preferable that the shading portion has not beenformed between each display area of the pixels mutually adjacent in thefirst direction. In addition, a color filter where an identical colorhas been successively arranged along the first direction and respectivecolors have been arranged in stripes along the second direction may beprovided. A display panel of the present invention can be incorporatedinto an image display device, and by providing the first direction as alens array direction of a lenticular lens of the image display device ora slit array direction of a parallax barrier, deterioration in displayquality caused by a shading portion of the display panel can beprevented.

According to the present invention, since the position of middle pointbetween both ends in the first direction of each display area in thepixels vary depending on the position in the second direction,occurrence of non-display area where no light reaches from pixels can besuppressed, thus deterioration in display quality caused by a shadingportion of the display panel can be prevented.

A lens according to the present invention comprises; a plurality ofcylindrical lenses whose directions in which optical axes extend varydepending on a direction orthogonal to an array direction. In thepresent invention, when this is used as optical unit of an image displaydevice, deterioration in display quality caused by a shading portion ofthe display panel can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an optical model diagram showing a method that displaysthree-dimensional image by a parallax barrier system;

FIG. 2 is a perspective view showing a lenticular lens;

FIG. 3 is an optical model diagram showing a method that displaysthree-dimensional image by a lenticular lens system;

FIG. 4 is a perspective view showing a display for simultaneouslydisplaying multiple images as set forth in Japanese Published UnexaminedPatent Application No. 332354/1994;

FIG. 5 is a plan view showing a conventional display panel whose pixelopening ratio in a lens array direction is 50%;

FIG. 6 is an optical model diagram of a three-dimensional image displaydevice by a lenticular lens system using the display panel shown in FIG.5;

FIG. 7 is an optical model diagram showing a three-dimensional imagedisplay device by a conventional parallax barrier system wherein aparallax barrier has been provided at a viewer's side;

FIG. 8 is an optical model diagram showing a three-dimensional imagedisplay device by a conventional parallax barrier system wherein aparallax barrier has been provided in the rear of a display panel;

FIG. 9 is a perspective view showing a part of an image display deviceof a first embodiment of the present invention;

FIG. 10 is a plan view showing a display panel 2 shown in FIG. 9;

FIG. 11 is a perspective view showing a portable terminal equipped withthe image display device according to the first embodiment of thepresent invention;

FIG. 12 is an optical model diagram of a section along a line A-A shownin FIG. 10;

FIG. 13 is an optical model diagram of a section along a line B-B shownin FIG. 10;

FIG. 14 is an optical model diagram of a section along a line C-C shownin FIG. 10;

FIG. 15 is an optical model diagram showing operations of the imagedisplay device of the first embodiment of the present invention;

FIG. 16 is a graph showing distribution of brightness on a view plane ofthe image display device 1 of the first embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis;

FIG. 17 is a plan view showing wiring positions in a display panel 2shown in FIG. 9;

FIG. 18 is a plan view showing a display panel of an image displaydevice of a second embodiment of the present invention;

FIG. 19 is an optical model diagram of a section along a line D-D shownin FIG. 18;

FIG. 20 is an optical model diagram of a section along a line E-E shownin FIG. 18;

FIG. 21 is an optical model diagram showing operations of the imagedisplay device of the second embodiment of the present invention;

FIG. 22 is a graph showing distribution of brightness on a view plane ofthe image display device of the second embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis;

FIG. 23 is a plan view showing a display panel of an image displaydevice of a third embodiment of the present invention;

FIG. 24 is a graph showing distribution of brightness on a view plane ofthe image display device of the third embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis;

FIG. 25 is a plan view showing a display panel of an image displaydevice of a fourth embodiment of the present invention;

FIG. 26 is a graph showing distribution of brightness on a view plane ofthe image display device of the fourth embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis;

FIG. 27 is a plan view showing a display panel of an image displaydevice of a fifth embodiment of the present invention;

FIG. 28 is an optical model diagram of a section along a line F-F shownin FIG. 27;

FIG. 29 is an optical model diagram of a section along a line G-G shownin FIG. 27;

FIG. 30 is an optical model diagram of a section along a line H-H shownin FIG. 27;

FIG. 31 is an optical model diagram showing operations of the imagedisplay device of the fifth embodiment of the present invention;

FIG. 32 is a graph showing distribution of brightness on a view plane ofthe image display device of the fifth embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis;

FIG. 33 is a plan view showing a display panel of an Image displaydevice of a sixth embodiment of the present invention;

FIG. 34 is a graph showing distribution of brightness on a view plane ofthe image display device of the sixth embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis;

FIG. 35 is a plan view showing a display panel of an image displaydevice of a seventh embodiment of the present invention;

FIG. 36 is a plan view showing a display panel of an image displaydevice of an eighth embodiment of the present invention;

FIG. 37 is a plan view showing a display panel of an image displaydevice of a ninth embodiment of the present invention;

FIG. 38 is an optical model diagram of a section along a line I-I shownin FIG. 37;

FIG. 39 is an optical model diagram of a section along a line J-J shownin FIG. 37;

FIG. 40 is an optical model diagram of a section along a line K-K shownin FIG. 37;

FIG. 41 is an optical model diagram showing operations of the imagedisplay device of the ninth embodiment of the present invention;

FIG. 42 is a perspective view showing a portable terminal of a tenthembodiment of the present invention;

FIG. 43 is an optical model diagram showing operations of the imagedisplay device of the tenth embodiment of the present invention;

FIG. 44 is a plan view showing a lens and a display panel of an imagedisplay device of an eleventh embodiment of the present invention;

FIG. 45 is a plan view showing a display panel of an image displaydevice of a twelfth embodiment of the present invention; and

FIG. 46 is a graph showing distribution of brightness on a view plane ofthe image display device of the twelfth embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, image display devices according to embodiments of thepresent invention will be described in detail with reference to theaccompanying drawings. First, description is given of an image displaydevice according to a first embodiment of the present invention. FIG. 9is a perspective view showing a part of an image display device of thepresent embodiment, and FIG. 10 is a plan view showing a display panelthereof. As shown in FIG. 9, in an image display device 1 of the presentembodiment, a lenticular lens 3, a display panel 2, and a light source(unillustrated) are provided in order from a viewer side. The displaypanel 2 is, for example, a transmission liquid crystal panel. Thisdisplay panel 2 is composed of a large number of display pixels, andeach display pixel is composed of a pair of adjacent first viewpointpixel 41 and second viewpoint pixel 42. Here, in FIG. 9, for the sake ofimprovement in visibility of the drawing, borders between cylindricallenses 3 a on the display panel are omitted, and the same applies to thefollowing drawings, as well.

In addition, the lenticular lens 3 is provided a plurality ofcylindrical lenses 3 a parallel to each other. In the following, alongitudinal direction of this cylindrical lens 3 a is provided as avertical direction 11, while an array direction of the cylindricallenses 3 a is provided as a horizontal direction 12. And, the lenticularlens 3 is arranged so that each cylindrical lens 3 a corresponds to anarray of a pair of adjacent first viewpoint pixel 41 and secondviewpoint pixel 42, namely, a display image along the vertical direction11. In addition, for each pixel of the display panel 2, an opening 5 anda shading portion 6 are provided. This shading portion 6 is forpreventing color mixture in an image and for providing wiring totransmit a display signal to the pixel.

As shown in FIG. 10, in the image display device of the presentembodiment, quadrangular openings 5 as being display areas are formed infirst viewpoint pixel 41 and second viewpoint pixel 42, and directionsin which sides mutually opposed in the horizontal direction 12 extendare not parallel to the vertical direction 11 but are tilted withrespect to the vertical direction 11. Namely, the openings 5 are inapproximately parallelogramic forms in a plan view. Therefore, openingposition of this display panel 2 varies depending on the position in thevertical direction 11. Concretely, a section along a line A-A, a sectionalong a line B-B, and a section along C-C shown in FIG. 10 are differentin the opening positions from each other. In addition, of the openings 5of pixels mutually adjacent in the vertical direction 11, sides whichare mutually opposed in the horizontal direction 12 are tilted inmutually opposite directions, and angles which are created between thedirections in which these sides extend and vertical direction 11 areidentical in size. Namely, a shape of the openings 5 of the respectivepixels is, in the vertical direction 11, line-symmetric with respect toedges of the pixels extending in the horizontal direction 12 as an axis.

FIG. 11 is a perspective view showing a portable terminal equipped withan image display device according to the present embodiment. As shown inFIG. 11, for example this image display device 1 is equipped with aportable telephone 9.

Next, description will be given of operations of the image displaydevice 1 constructed as described above, namely, an image display methodin the image display device 1. FIG. 12 is an optical model diagram of asection along a line A-A shown in FIG. 10. As shown in FIG. 12, in theimage display device 1 of the present embodiment, when a light source 10is lit, light emitted from the light source 10 is made incident into thedisplay panel 2. In addition, on the other hand, the display panel 2 isdriven by a control device (unillustrated), and a first viewpoint imageand a second viewpoint image are displayed, respectively, on the firstviewpoint pixel 41 and second viewpoint pixel 42 of each display pixel.And, lights made incident into the first viewpoint pixel 41 and secondviewpoint pixel 42 of the display panel 2 penetrate through the openings5 of these pixels, and furthermore, these are refracted by thelenticular lens 3, and are emitted toward areas EL and ER, respectively.At this time, by a viewer positioning his/her left eye 61 at the area ELand his/her right eye 62 at the area ER, the first viewpoint image isinputted into the left eye 61, and also the second viewpoint image isinputted into the right eye 62. For example, when the first viewpointimage and second viewpoint image are parallax images to compose athree-dimensional image, the first viewpoint image is an image for theleft eye 61, and the second viewpoint image is an image for the righteye 62, the viewer can recognize a three-dimensional image. However, ina section along the A-A line, non-display areas EB caused by the shadingportion 6 occur at both sides of the display areas EL and ER.

In addition, FIG. 13 is an optical model diagram of a section along aline B-B shown in FIG. 10. As shown in FIG. 13, in the section along theline B-B, position of the openings 5 of the first viewpoint pixel 41 andsecond viewpoint pixel 42 is provided at a more right side in thedrawing than in the section along the line A-A shown in FIG. 10.Therefore, in the section along the line B-B, non-display areas EB areone-sided to a right side in the drawing with respect to a centerline xof a view plane. Here, operations other than the above are the same asthose with the section along the line A-A as described above.

Furthermore, FIG. 14 is an optical model diagram of a section along aline C-C shown in FIG. 10. As shown in FIG. 14, in a section along theline C-C, position of the openings 5 of the first viewpoint pixel 41 andsecond viewpoint pixel 42 is provided at a more left side in the drawingthan in the section along the line A-A shown in FIG. 10. Therefore, inthe section along the line C-C, non-display areas EB are one-sided to aleft side in the drawing with respect to a centerline x of a view plane.Here, operations other than the above are the same as those with thesection along the line A-A as described above.

FIG. 15 is an optical model diagram showing operations of the imagedisplay device 1 of the present embodiment. The cylindrical lenses 3 ato compose the lenticular lens 3 are lenses wherein lens elements areone-dimensionally successive and have no lens effect in the verticaldirection 11, which is a successive direction thereof. Therefore, inactuality, the display areas EL and ER in the section along the line A-A(FIG. 12), section along the line B-B (FIG. 13), and section along theline C-C (FIG. 14) are synthesized and made into display areas EL and ERshown in FIG. 15. As a result, in the image display device 1 of thepresent embodiment, since the non-display area EB is eliminated,deterioration in display quality caused by the shading portion 6 can besuppressed.

FIG. 16 is a graph showing distribution of brightness on a view plane ofthe image display device 1 of the first embodiment of the presentinvention while taking a view position on the horizontal axis andbrightness on the vertical axis. As shown in FIG. 16, for the imagedisplay device 1 of the present embodiment, since an influence of theshading portion 6 is relieved by the foregoing effect, no non-displayarea EB where no light reaches from each pixel occurs.

In general, when the array direction of the first viewpoint pixel 41 andsecond viewpoint pixel 42 is not parallel to the longitudinal directionof the cylindrical lens 3 a, display quality is deteriorated sinceimages are observed in a superimposed manner. Therefore, in the imagedisplay device 1 of the present embodiment, of the openings 5 mutuallyadjacent in the horizontal direction 12, sides which are mutuallyopposed in the horizontal direction 12 are tilted in mutually oppositedirections with respect to the vertical direction 11, and angles whichare created between the direction in which these sides extend andvertical direction 11 are identical in absolute values. Namely, a shapeof the openings 5 is line-symmetric with respect to edges of the pixelsextending in the horizontal direction 12 as an axis. Accordingly, sincethe first viewpoint pixel 41 and second viewpoint pixel 42 arerespectively arrayed along the vertical direction 11, the arraydirection of the first viewpoint pixel 41 and second viewpoint pixel 42and the longitudinal direction of the cylindrical lens 3 a can be madeparallel to each other. Therefore, in the image display device 1 of thepresent embodiment, no problem such that images are observed in asuperimposed manner occurs.

In addition, in the display device 1 of the present embodiment, sincethe shapes of the openings 5 surrounded by the shading portion 6 areapproximately parallelogramic in a plan view, two of the four cornershave obtuse angles. In general, when a light shading portion 6 isfabricated by a low-cost manufacturing method, the corners are roundedto lower the opening ratio, however, the image display device 1 of thepresent embodiment is small in the number of corners, and furthermore,half thereof can be constructed with obtuse angles, therefore, roundingof the corners can be suppressed to a minimum. As a result, lowering inthe opening ratio caused by the manufacturing method can be suppressed.For this, in particular, a great effect can be obtained when theinvention is applied to a high-definition image display device with asmall pixel pitch.

FIG. 17 is a plan view showing wiring positions in a display panel 2shown in FIG. 9. In the image display device 1 of the presentembodiment, although directions in which sides which are mutuallyopposed in the horizontal direction 12 extend are not parallel to thevertical direction 11, as shown in FIG. 17, it is preferable that thelongitudinal direction of wiring 60 arranged between the openings 5adjacent in the horizontal direction 12 is also not parallel to thevertical direction 11. Thereby, since an overlapping margin between thewiring 60 and shading portion 6 during assembly can be increased, theyield in manufacturing is improved.

Furthermore, since the image display device 1 of the present embodimentuses the lenticular lens 3 as an image sorting component, no such blackstriped pattern caused by a barrier as in an image display using aparallax barrier occurs, thus light loss is small. Here, in theforegoing, although a description has been given for a case with twoviewpoints, the present invention is not limited hereto, and similareffects can also be obtained when an image display device is providedwith multiple viewpoints of three viewpoints or more.

In addition, the image display device 1 of the present embodiment can befavorably applied to a portable apparatus such as a portable telephone,which can display an excellent image. In particular, when athree-dimensional image is displayed on this image display device 1,unlike when this is applied to a large-size display device, since aviewer can arbitrarily adjust a positional relationship between bothhis/her eyes and a display screen, he/she can swiftly find out anoptimal visible range. Furthermore, when a planar image of differentcontents is displayed on the image display device 1 of the presentembodiment, unlike when this is applied to a large-size display device,since a viewer can view the planar image of different contents by onlychanging angles of the image display device, convenience is greatlyimproved. Still furthermore, the image display device 1 of the presentembodiment can be applied not only to portable telephones but also tovarious types of portable terminal devices such as portable terminals,PDAs (Personal Digital Assistant), game machines, digital cameras, anddigital video cameras.

Here, in the image display device 1 of the present embodiment, althougha transmissive liquid crystal display panel has been used as a displaypanel, the present invention is not limited hereto, and a reflectiveliquid crystal display panel or a semi-transmissive liquid crystaldisplay panel where a transmitting area and a reflecting area areprovided in each pixel may be used. In addition, a driving method for aliquid crystal display panel may be of an active matrix system such as aTFT (Thin Film Transistor) system, a TED (Thin Film Diode) system andthe like, or it may be of a passive matrix system such as an STN (SuperTwisted Nematic liquid crystal) system and the like. Furthermore, forthe display panel, a display panel other than a liquid crystal displaypanel, for example, an organic electroluminescent display panel, aplasma display panel, a CRT (Cathode-Ray Tube) display panel, an LED(Light Emitting Diode) display panel, a field emission display panel, ora PALC (Plasma Address Liquid Crystal) display may be used. Stillfurthermore, in the image display device 1 of the present embodiment, acolor image may be displayed by a time-sharing system.

Next, description is given of an image display device according to asecond embodiment of the present invention. FIG. 18 is a plan viewshowing a display panel of an image display device of the presentembodiment. As shown in FIG. 18, in an image display device 13 of thepresent embodiment, of respective openings 15 of first viewpoint pixels41 and second viewpoint pixel 42, sides which intersect with straightlines extending in a horizontal direction 12 are composed of straightlines parallel to a vertical direction 11 and straight lines vertical tothe same, and the openings 15 have shapes with a dislocation in thehorizontal direction 12 in the vicinities of center portions.Accordingly, position of the openings in this display panel 14 variesdepending on the position in the vertical direction 11.

FIG. 19 is an optical model diagram of a section along a line D-D shownin FIG. 18. As shown in FIG. 19, in the section along the line D-D,position of the openings 15 of the first viewpoint pixel 41 and secondviewpoint pixel 42 is provided rightward in the drawing. Therefore, inthe section along the line D-D, non-display areas ES are one-sided tothe right side in the drawing with respect to a centerline x of a viewplane. In addition, FIG. 20 is an optical model diagram of a sectionalong a line E-E shown in FIG. 18. As shown in FIG. 20, in the sectionalong the line E-E, position of the openings 15 of the first viewpointpixel 41 and second viewpoint pixel 42 is provided leftward in thedrawing. Therefore, in the section along the line E-E, unlike theaforementioned section along the line D-D, non-display areas EB areone-sided to the left side in the drawing with respect to a centerline xof a view plane.

FIG. 21 is an optical model diagram showing operations of the imagedisplay device 13 of the present embodiment. In this image displaydevice 13, similar to the aforementioned first embodiment, since alenticular lens is used, the display areas EL and ER in the sectionalong the line D-D (FIG. 19) and the section along the line E-E (FIG.20) are synthesized and made into display areas EL and ER shown in FIG.21. As a result, in the image display device 13 of the presentembodiment, since the non-display areas EB are eliminated, deteriorationin display quality caused by a shading portion 16 can be suppressed.

FIG. 22 is a graph showing distribution of brightness on a view plane ofthe image display device of the second embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis. As shown in FIG. 22, for the imagedisplay device 13 of the present embodiment, since an influence of theshading portion 16 is relieved by the foregoing effect, no non-displayareas EB where no light reaches from each pixel occur. In addition,since brightness in the vicinity of an image boundary can be madegreater than that of the image display device 1 of the aforementionedembodiment, an effect to suppress deterioration in display qualitycaused by the shading portion 16 is greater.

In addition, in the image display device 13 of the present embodiment,since sides of the openings 15 which intersect with straight linesextending in the horizontal direction 12 are composed of straight linesparallel to a vertical direction 11 and straight lines vertical to thesame, the respective openings 15 of the first viewpoint pixel 41 andsecond viewpoint pixel 42 can be made larger than those of the imagedisplay device 1 of the aforementioned first embodiment. As a result,since illuminance at the boundary between the respective viewpointimages can be heightened, in comparison with the image display device 1of the aforementioned first embodiment, an effect to suppressdeterioration in display quality caused by the shading portion 16 isgreat.

However, for the image display device 13 of the present embodiment,since wiring must be arranged on the shading portion 16 formed betweenthe openings 15 mutually adjacent in the horizontal direction 12 so asto become parallel and vertical to the vertical direction 11, the wiringlength is made longer than that of the image display device of theaforementioned first embodiment, and a wiring time constant caused bywiring resistance and capacity is increased. Therefore, as regardsdriving the display panel, the image display device 1 of theaforementioned first embodiment is more advantageous than the imagedisplay device 13 of the present embodiment. Here, in the image displaydevice 13 of the present embodiment, aspects of the construction andoperations other than the above are the same as those of the imagedisplay device 1 of the aforementioned first embodiment.

Next, description is given of an image display device according to athird embodiment of the present invention. FIG. 23 is a plan viewshowing a display panel of an image display device of the thirdembodiment of the present invention. As shown in FIG. 23, in the imagedisplay device of the present embodiment, sides of openings 25 of thedisplay panel which intersect with straight lines extending in ahorizontal direction 12 are composed of curved lines. Namely, sides ofopenings 25 opposed in a horizontal direction 12 are composed of curvedlines.

FIG. 24 is a graph showing distribution of brightness on a view plane ofthe image display device of the third embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis. In the image display device of thepresent embodiment, since the sides of the openings 25 of the displaypanel which intersect with straight lines extending in the horizontaldirection 12 are composed of curved lines, distribution of brightness ona view plane can be made into an arbitrary shape, and for example, intoa shape of distribution as shown in FIG. 24, setting with a higherdegree of freedom according to desirable optical characteristics becomespossible.

In addition, in the image display device of the present embodiment, thenumber of corners of each opening 25 surrounded by a shading portion 26can be minimized to four, and furthermore, all corners can be made intoright angles. Namely, no such acute-angled corners are formed as in theimage display device 1 of the aforementioned first embodiment. Thereby,in comparison with the image display devices of the aforementioned firstand second embodiments, a decline in the opening ratio caused by themanufacturing method can be suppressed. Here, aspects of theconstruction and operations of the image display device of the presentembodiment other than the above are the same as those of the imagedisplay device 1 of the aforementioned first embodiment.

Next, description is given of an image display device according to afourth embodiment of the present invention. FIG. 25 is a plan viewshowing a display panel of an image display device of the fourthembodiment of the present invention. As shown in FIG. 25, in the imagedisplay device of the present embodiment, provided are openings 35 in ashape where three rectangles having equal areas in a plan view have beenstaggered in a vertical direction 11 and connected in a horizontaldirection 12. These openings 35 have been formed so that shapes ofpixels that are mutually adjacent in the horizontal direction 12 becomeidentical and a form of pixels that are mutually adjacent in thevertical direction 11 becomes line-symmetric. Accordingly, therespective pixels have a fixed opening ratio in the vertical direction11 at an arbitrary position in the horizontal direction 12.

FIG. 26 is a graph showing distribution of brightness on a view plane ofthe image display device of the fourth embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis. As shown in FIG. 26, in the imagedisplay device of the present embodiment, since the opening ratio in thevertical direction 11 of the respective pixels is fixed at an arbitraryposition in the horizontal direction, brightness distribution withrespect to the viewing position can be fixed, thus deterioration indisplay quality caused by a shading portion 36 can be completelyeliminated. Here, aspects of the construction and operations of theimage display device of the present embodiment other than the above arethe same as those of the image display device 13 of the aforementionedsecond embodiment. This display panel can also be applied to the imagedisplay device of the aforementioned third embodiment.

Next, description is given of an image display device according to afifth embodiment of the present invention. FIG. 27 is a plan viewshowing a display panel of an image display device of the fifthembodiment of the present invention. As shown in FIG. 27, in an imagedisplay device 43 of the present embodiment, the openings in the displaypanel of the image display device of the aforementioned first embodimentare each divided into two in a horizontal direction 12 by a shadingportion. Namely, in the first viewpoint pixel 41 and second viewpointpixel 42, two mutually parallel openings 45 are provided, respectively.Moreover, sides of openings 45 which intersect with straight linesextending in the horizontal direction 12 are not parallel to a verticaldirection 11 but are tilted with respect to the vertical direction 11.

Next, description will be given of operations of the image displaydevice 43 constructed as described above, namely, an image displaymethod in the image display device 43. FIG. 28 is an optical modeldiagram of a section along a line F-F shown in FIG. 27. As shown in FIG.28, in the section along the line F-F of a display panel 44, a shadingportion 46 is provided at a center portion of each pixel. Therefore,non-display areas EB caused by the shading portion 46 occur at bothsides and center of display areas EL and ER. In addition, FIG. 29 is anoptical model diagram of a section along a line G-G shown in FIG. 27. Asshown in FIG. 29, in the section along the line G-G, shading portions 46are provided rightward in the pixels. Therefore, non-display areas EBoccur at right sides of display areas EL and ER. Furthermore, FIG. 30 isan optical model diagram of a section along a line H-H shown in FIG. 27.As shown in FIG. 30, in the section along the line H-H, shading portions46 are provided leftward in the pixels. Therefore, non-display areas EBoccur at left sides of display areas EL and ER.

FIG. 31 is an optical model diagram showing operations of the imagedisplay device 43 of the present embodiment. In this image displaydevice 43, similar to the aforementioned first embodiment, since alenticular lens is used, the display areas EL and ER in the sectionalong the line F-F (FIG. 28), section along the line G-G (FIG. 29), andsection along the line H-H (FIG. 30) are synthesized and made intodisplay areas EL and ER shown in FIG. 31. As a result, in the imagedisplay device 43 of the present embodiment, since the non-display areasES are eliminated, deterioration in display quality caused by theshading portion 46 can be suppressed.

FIG. 32 is a graph showing distribution of brightness on a view plane ofthe image display device of the fifth embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis. As shown in FIG. 32, in such a casewhere, at a center portion of each pixel, provided is a shading portion46 to divide the pixel in the horizontal direction 12 as in the imagedisplay device 43 of the present embodiment, as well, deterioration indisplay quality caused by the shading portion 46 can be suppressed.

Here, under the shading portion 46 to split pixels provided at thecenter portions of pixels, storage capacitance provided for each of thepixels and wiring to connect the storage capacitance can be arranged. Inaddition, aspects of the construction and operations other than theabove of the image display device 43 of the present embodiment are thesame as those of the image display device 1 of the aforementioned firstembodiment. Furthermore, this display panel 44 can be applied to theimage display devices of the aforementioned first through fourthembodiments.

Next, description is given of an image display device according to asixth embodiment of the present invention. FIG. 33 is a plan viewshowing a display panel of an image display device of the sixthembodiment of the present invention. As shown in FIG. 33, in the imagedisplay device of the present embodiment, the openings 5 in the displaypanel 2 of the image display device 1 of the aforementioned firstembodiment shown in FIG. 17 are each divided by a plurality of mutuallyparallel comb electrodes 57. These comb electrodes 57 are formedparallel to sides of a shading portion 6 extending between openingsadjacent in a horizontal direction 12, not parallel to a verticaldirection 11, and with a predetermined angle with respect to thevertical direction 11. And, directions of pixels adjacent in thehorizontal direction 12 in which the comb electrodes 57 extend aremutually parallel, and the comb electrodes 57 in pixels adjacent in thevertical direction 11 are symmetric with respect to sides of the shadingportion 6 extending in the horizontal direction 12 as an axis. Here, inFIG. 33, for the sake of improvement in visibility of the drawing, thecomb electrodes 57 have been shown with hatching.

FIG. 34 is a graph showing distribution of brightness on a view plane ofthe image display device of the sixth embodiment of the presentinvention while taking a viewing position on the horizontal axis andbrightness on the vertical axis. As shown in FIG. 34, in such a casewhere the openings of respective pixels in the display panel have beendivided in the horizontal direction 12 by the comb electrodes 57 as inthe image display device of the present embodiment, as well, effectssimilar to those in the image display device 1 of the first embodimentcan be obtained, thus deterioration in display quality caused by thecomb electrodes 57 can be suppressed.

In the image display device of the present embodiment, since the combelectrodes 57 have been provided at openings of the respective pixels,electric fields can be generated in the horizontal direction 12 of thedisplay panel, and this can be appropriately applied for driving aliquid crystal panel in an In-Plane Switching mode. In addition, thecomb electrodes 57 of this image display device can be eithernon-transparent electrodes formed of a metallic material such asaluminum or transparent electrodes formed of ITO (indium tin oxide) orthe like, and in either case, similar effects can be obtained. In a casewhere the comb electrodes 57 are provided at openings of the respectiveelectrodes, even when these comb electrodes 57 are transparentelectrodes, on the comb electrodes 57, areas where, since horizontalelectric fields are not sufficiently applied, liquid crystals cannot bedriven by horizontal electric fields and light is not sufficientlypenetrated occur, however, as in the image display device of the presentembodiment, by making directions in which the comb electrodes 57 extendare made mutually parallel in pixels adjacent in the horizontaldirection 12 and making comb electrodes 57 in pixels adjacent in thevertical direction 11 symmetric with respect to sides of the shadingportion 6 extending in the horizontal direction 12 as an axis, thenon-display areas are eliminated, thus deterioration in display qualitycaused by the comb electrodes 57 can be suppressed.

As mentioned above, the image display device of the present embodimentis effective when the display panel is a liquid crystal display paneland this liquid crystal display panel is driven in a mode where, as inthe above-described In-Plane Switching mode, areas which do notsufficiently penetrate light, namely, non-display areas occur atopenings of the respective pixels. As liquid crystal driving modes wherenon-display areas occur as such, for example, a Fringe Field Switchingmode and an Advanced Fringe Field Switching mode, which are horizontalelectric field modes similar to the In-Plane Switching mode, aMulti-Domain Vertical Alignment mode, a Patterned Vertical Alignmentmode and an Advanced Super View mode, which are a multi-domainedvertical orientation mode, and the like can be mentioned. With thismulti-domained vertical orientation mode, areas that do not penetratelight occur at boundary between the domains. Here, aspects of theconstruction and operations of the image display device of the presentembodiment other than the above are the same as those of the imagedisplay device of the aforementioned fifth embodiment.

Next, description is given of an image display device according to aseventh embodiment of the present invention. FIG. 35 is a plan viewshowing a display panel of an image display device of the seventhembodiment of the present invention. As shown in FIG. 35, in the imagedisplay device of the present embodiment, sides of openings 65 whichintersect with straight lines extending in a horizontal direction 12 arebent multiple times.

In the image display device of the present embodiment, since the sidesof the openings 65 which intersect with straight lines extending in thehorizontal direction 12 are bent multiple times, angles of these sidesbecome less conspicuous than in the image display device of theaforementioned first embodiment, thus display quality can further beimproved. Such shapes of the openings 65 are particularly effective whenthe pixel pitch is great. Here, aspects of the construction andoperations of the image display device of the present embodiment otherthan the above are the same as those of the image display device 1 ofthe aforementioned first embodiment. Moreover, this display panel canalso be applied to the image display devices of the aforementioned firstthrough sixth embodiments.

Next, description is given of an image display device according to aneighth embodiment of the present invention. FIG. 36 is a plan viewshowing a display panel of an image display device of the eighthembodiment of the present invention. As shown in FIG. 36, the imagedisplay device of the present embodiment is the same as the imagedisplay device 1 of the aforementioned first embodiment except for thatwiring 60 is provided to extend in a direction parallel to a verticaldirection 11.

In the image display device of the present embodiment, althoughnon-display areas caused by the wiring 60 occur, since sides of openings5 which are mutually opposed in a horizontal direction 12 have been madenot parallel to the vertical direction 11 and the openings of each pixelin the vertical direction 11 have been varied, deterioration in displayquality caused by sharing portions 6 can be suppressed than in aconventional image display device. On the other hand, since the wiring60 is made parallel to the vertical direction 11, in comparison with theimage display device 1 of the aforementioned first embodiment, thewiring 60 length can be shortened, and a wiring time constant caused bywiring resistance and capacity can be lowered. This is advantageous indriving the display panel. Here, aspects of the construction andoperations of the image display device of the present embodiment otherthan the above are the same as those of the image display device 1 ofthe aforementioned first embodiment. In addition, this display panel canalso be applied to the image display devices of the aforementioned firstthrough seventh embodiment.

Next, description is given of an image display device according to aninth embodiment of the present invention. FIG. 37 is a plan viewshowing a display panel of an image display device of the ninthembodiment of the present invention. As shown in FIG. 37, for an imagedisplay device 81 of the present embodiment, a parallax barrier 8 isprovided in place of a lenticular lens. Here, the shape of therespective pixels are the same as that of the image display device ofthe first embodiment shown in FIG. 2, and in the present embodiment,aspects of the construction other than the above are the same as thoseof the image display device 1 of the aforementioned first embodiment.

Next, description will be given of operations of the image displaydevice of the present embodiment constructed as described above. FIG. 38is an optical model diagram of a section along a line I-I shown in FIG.37. As shown in FIG. 38, in the image display device 81 of the presentembodiment, when a light source 10 is lit, light emitted from the lightsource 10 is made incident into a display panel 2. In addition, on theother hand, the display panel 2 is driven by a control device(unillustrated), and a first viewpoint image and a second viewpointimage are displayed, respectively, on a first viewpoint pixel 41 and asecond viewpoint pixel 42 of each display pixel. And, lights madeincident into the first viewpoint pixel 41 and second viewpoint pixel 42of the display panel 2 penetrate through the openings 5 of these pixels,and after penetrating through these pixels, proceeds to the parallaxbarrier 8. Furthermore, these lights penetrate through slits 8 a of theparallax barrier 8, and are emitted toward areas EL and ER,respectively. At this time, by a viewer positioning his/her left eye 61at the area EL and positioning his/her right eye 62 at the area ER, thefirst viewpoint image is inputted into the left eye 61, and also thesecond viewpoint image is inputted into the right eye 62. For example,when the first viewpoint image and second viewpoint image are parallaximages to compose a three-dimensional image, the first image is an imagefor the left eye 61, and the second image is an image for the right eye62, the viewer can recognize a three-dimensional image. However, on bothsides of the display areas EL and ER, non-display areas EB caused by ashading portion 6 occur.

In addition, FIG. 39 is an optical model diagram of a section along aline J-J shown in FIG. 37. As shown in FIG. 39, in the section along theline J-J, positions of openings 5 of the first viewpoint pixel 41 andsecond viewpoint pixel 42 are provided at a more right side in thedrawing than in the section along the line I-I shown in FIG. 38.Therefore, in the section along the line J-J, non-display areas EB areone-sided to a right side in the drawing with respect to a centerline xof a view plane. Here, operations other than the above are the same asthose with the section along the line I-I as described above.

Furthermore, FIG. 40 is an optical model diagram of a section along aline K-K shown in FIG. 37. As shown in FIG. 40, in a section along theline K-K, positions of openings 5 of the first viewpoint pixel 41 andsecond viewpoint pixel 42 are provided at a more left side in thedrawing than in the section along the line I-I shown in FIG. 38.Therefore, in the section along the line K-K, non-display areas EB areone-sided to a left side in the drawing with respect to a centerline xof a view plane. Here, operations other than the above are the same asthose with the section along the line I-I as described above.

FIG. 41 is an optical model diagram showing operations of the imagedisplay device of the ninth embodiment of the present invention. In theimage display device of the present embodiment, opening of the slits 8 aof the parallax barrier 8 are one-dimensionally successive and have noshading effect in a vertical direction, which is a successive directionthereof. Therefore, in actuality, the display areas EL and ER in thesection along the line I-I (FIG. 38), section along the line J-J (FIG.39), and section along the line K-K (FIG. 40) are synthesized and madeinto display areas EL and ER shown in FIG. 41. As a result, in the imagedisplay device of the present embodiment, since the non-display areas EBare eliminated, deterioration in display quality caused by the shadingportion 6 can be suppressed.

In the image display device of the present embodiment, by use of theparallax barrier, provided is an advantage in that deterioration inquality of a display image owing to a lens pattern does not occur incomparison with the case where a lenticular lens is used. Effects of theimage display device of the present embodiment other than the above arethe same as those of the image display device 1 of the aforementionedfirst embodiment. Here, in the image display devices of theaforementioned second through eighth embodiments, as well, a parallaxbarrier can be used in place of a lenticular lens.

Next, description is given of a portable terminal device according to atenth embodiment of the present invention. FIG. 42 is a perspective viewshowing a portable terminal of the present embodiment. As shown in FIG.42, for a portable terminal device 99 of the present embodiment,cylindrical lenses 93 a to compose a lenticular lens of an image displaydevice 91 have been arrayed in a vertical direction 11. Namely, thelongitudinal direction of the cylindrical lenses 93 a is a horizontaldirection 12. Here, in the image display device of the portable terminaldevice 99 of the present embodiment, aspects of the construction otherthan the above are the same as those of the image display device of theaforementioned first embodiment.

Next, description is given of operations of the image display device 91of the portable terminal device 99 according to the present embodiment.FIG. 43 is an optical model diagram showing operations of this imagedisplay device. As shown in FIG. 43, in the image display device 91 ofthe portable terminal device 99 of the present embodiment, when a lightsource 10 is lit, light emitted from the light source 10 is madeincident into a display panel 2. At this time, the display panel 2 isdriven by a control device (unillustrated), whereby a first viewpointimage and a second viewpoint image are displayed, respectively, on afirst viewpoint pixel 41 and a second viewpoint pixel 42 of each displaypixel. And, lights made incident into the first viewpoint pixel 41 andsecond viewpoint pixel 42 of the display panel 2 penetrate through thesepixels, are refracted by the cylindrical lenses 3 a of the lenticularlens 3, and are emitted toward areas E1 and E2, respectively. At thistime, when a viewer positions both his/her eyes at the area E1, he/shecan observe the first viewpoint image, and when he/she positions bothhis/her eyes at the area E2, he/she can view the second viewpoint image.

In the portable terminal device 99 of the present embodiment, since thecylindrical lenses 93 a to compose the lenticular lens 93 of the imagedisplay device 91 have been arrayed in the vertical direction 11, aviewer can view the first viewpoint image or second viewpoint image byonly changing angles of the portable terminal device 99. In particular,when a first viewpoint image and a second viewpoint image have arelationship to each other, since the respective images can be comparedby a simple operation of changing viewing angles, convenience is greatlyimproved. For example, when images for a plurality of viewpoints arearrayed in the horizontal direction 12, since positions to view imagesat different viewpoints occur for the right eye and left eye, there maybe a case where the viewer is confused and fails to recognize images atthe respective viewpoints. However, as in the portable telephone device99 of the present embodiment, when images for a plurality of viewpointsare arrayed in the vertical direction 11, since the viewer can alwaysview images for respective viewpoints with both eyes, images at therespective viewpoints can be recognized without confusion. Here, effectsof the portable terminal device 99 of the present embodiment other thanthe above are the same as those of the aforementioned first embodiment.Here, in the aforementioned second through ninth embodiments, as well,the present embodiment can be applied.

Next, description is given of an image display device according to aneleventh embodiment of the present invention. FIG. 44 is a plan viewshowing a lens and a display panel of an image display device of thepresent embodiment. As shown in FIG. 44, the image display device of thepresent embodiment is, unlike the image display device of theaforementioned first embodiment, in a conventional shape whereindirections in which sides of openings 95 of pixels mutually opposed in ahorizontal direction 12 are parallel to a vertical direction 11, andmoreover, position of the openings 95 does not vary depending on theposition in the vertical direction 11. And, directions in which opticalaxes of cylindrical lenses 97 a extend vary depending on the position inthe vertical direction 11.

In the image display device of the present embodiment, since thepositions of middle points between both ends in the horizontal direction12 of the pixel openings 95 with respect to the directions in which theoptical axes of the lenses extend vary according to the verticaldirection 11, deterioration in display quality caused by a shadingportion 96 can further be suppressed than in a conventional imagedisplay device. In addition, since a general-purpose display panel canbe used, a reduction in cost is possible. Here, aspects of theconstruction and operations of the image display device of the presentembodiment other than the above are the same as those of the imagedisplay device 1 of the aforementioned embodiment. In addition, thislens can also be applied to the image display devices of theaforementioned first through ninth embodiments.

Next, description is given of an image display device according to atwelfth embodiment of the present invention. FIG. 45 is a plan viewshowing a display panel of an image display device of the embodiment.Here, in FIG. 45, for the sake of improvement in visibility of thedrawing, wiring 70 has been shown with hatching. In the image displaydevice 1 of the first embodiment shown in FIG. 17, the openings 5 of thedisplay panel 2 are approximately parallelogramic in terms of a planview, whereas in the image display device of the present embodiment, asshown in FIG. 45, openings 75 have shapes including trapezoids in a planview. Concretely, the openings 75 have hexagonal shapes each formed byarranging a left-right symmetric trapezoid and a rectangle whose longside length is equal to a length of the lower base of this trapezoid sothat the lower base of the trapezoid and the long side of the rectanglemutually make contact. Namely, a shape of the openings 75 is left-rightsymmetric with respect to a line segment extending in a verticaldirection 11, and as sides to form this openings 75, this is providedwith a pair of sides which are tilted in mutually opposite directionswith respect to the vertical direction 11 and are identical in the sizeof angles produced between directions of extension thereof and thevertical direction 11.

Accordingly, in a area between the pair of sides tilted with respect tothe vertical direction 11, although end portions in a horizontaldirection 12 of the openings 75 vary in their positions in thehorizontal direction 12 depending on the position in the verticaldirection 11, middle points between both ends in the horizontaldirection 12 do not vary in their positions in the horizontal direction12 irrespective of the position in the vertical direction 11. And, sincethe longitudinal direction of cylindrical lenses 3 a to compose alenticular lens is parallel to the vertical direction 11, although thedistance between the end in the horizontal direction 12 of the openings75 of the display panel and optical axes of the cylindrical lenses 3 avaries depending on the position in the vertical direction 11, thedistance between line segments joining middle points between the bothends in the horizontal direction 12 of the openings 75 of the displaypanel and optical axes of the cylindrical lenses 3 a is relatively fixedirrespective of the position in the vertical direction 11. Namely, thepositions of end in the horizontal direction 12 of openings 75 of thedisplay panel and the positions of optical axes of the cylindricallenses 3 a are relatively different in the vertical direction 11, andthe positions of middle points between both ends in the horizontaldirection 12 of the openings 75 of the display panel and the positionsof optical axes of the cylindrical lenses 3 a are relatively invariable.

Furthermore, the openings 75 mutually adjacent in the vertical direction11 of this display panel are arranged so as to be line-symmetric withrespect to line segments extending in the horizontal direction 12. Inaddition, the openings 75 mutually adjacent in the horizontal directionare arranged so as to be point-symmetric with respect to a middle pointbetween intersection points between a line segment joining middle pointsbetween the both ends in the vertical direction 11 thereof and a linesegment joining middle points between the both ends in the horizontaldirection 12. Therefore, the widths of the openings 75 in the verticaldirection 11 are, when those of the openings 75 mutually adjacent in thehorizontal direction 12 are also added, almost fixed irrespective of theposition in the horizontal direction 12.

Here, a shading portion 76 is not provided at areas between the sidestilted with respect to the vertical direction 11 of areas between theopenings 75 mutually adjacent in the horizontal direction 12, that are,at edges of pixels tilted with respect to the vertical direction 11 ofpixels, but is provided only at areas between the sides extending in adirection parallel to the horizontal direction 12 of areas between theopenings 75 mutually adjacent in the vertical direction 11, that are, atedges of pixels extending in the horizontal direction 12. And, theopenings 75 mutually adjacent in the horizontal direction 12 aresectioned by the wiring 70, and are shaded by this wiring 70.

FIG. 46 is a graph showing distribution of brightness on a view plane ofthe image display device of the present embodiment while taking aviewing position on the horizontal axis and brightness on the verticalaxis. As in the image display device of the present embodiment, bymaking the openings 75 of the respective pixels of the display panel inthe shapes including trapezoids in a plan view, furthermore, arrangingthe openings 75 mutually adjacent in the vertical direction 11 so as tobe line-symmetric with respect to line segments extending in thehorizontal direction 12, and also arranging the openings 75 mutuallyadjacent in the horizontal direction 12 so as to be point-symmetric withrespect to a middle point between the intersection points between theline segment joining middle points between the both ends in the verticaldirection 11 thereof and line segment joining middle points between theboth ends in the horizontal direction 12, the opening ratio in thevertical direction at an arbitrary position in the horizontal direction12 of the respective pixels can be fixed, therefore, as shown in FIG.46, brightness distribution with respect to the viewing position can befixed. As a result, deterioration in display quality caused by theshading portion 76 can be completely eliminated.

Here, in the image display device of the present embodiment, since noshading portion 76 has been provided in an area between the pair ofsides tilted with respect to the vertical direction, even when apositional error margin in the horizontal direction 12 when forming ashading portion 76 is great, influence exerted to the opening ratio issmall. Namely, the positional margin in the horizontal direction 12 canbe set great to realize a high opening ratio. Such a shape provides agreat effect, in particular, when a shading portion 76 is formed on asubstrate opposed to a substrate on which the wiring 70 has been formed.

Furthermore, in the image display device of the present embodiment,since the shapes of the openings 75 are hexagonal shapes each formed byarranging, in a plan view, a trapezoid and a rectangle whose long sidelength is equal to a length of the lower base of this trapezoid so thatthe lower base of the trapezoid and the long side of the rectanglemutually make contact, all corners are obtuse or right angles.Therefore, rounding of the corners of the shading portion 76 caused bythe forming method can be suppressed to a minimum, thus a decline in theopening ratio caused by the manufacturing method can be suppressed.

Still furthermore, in the image display device of the presentembodiment, when a striped color filter is provided on the display panelfor a color display, the direction of a same-color sequence of the colorfilter is preferably made in the horizontal direction 12. Thereby, itbecomes unnecessary to shade same-color areas of the color filter, and arectangular form can be realized, therefore, the color filtermanufacturing can be easily manufactured, a reduction in cost can berealized. Here, aspects of the construction and operations other thanthe above are the same as those of the image display device 1 of theaforementioned first embodiment.

What is claimed is:
 1. A lenticular lens comprising: cylindrical lensesaligned in a first direction, each of the cylindrical lenses beingformed of a series of lenses aligned in a second direction orthogonal tothe first direction such that the optical axes of the lenses areinclined toward alternately opposite directions relative to the seconddirection, to form a bend between adjacent lenses in the seconddirection, a cross section of each of the lenses on a first planeorthogonal to the optical axis of the lens having a curvature, everycross section of the lens on a plane parallel to the first plane beingidentical.
 2. The lenticular lens according to claim 1, wherein thebends provided to the respective cylindrical lenses aligned in the firstdirection are on a same straight line.
 3. The lenticular lens accordingto claim 2, wherein the straight line is parallel to the firstdirection.
 4. The lenticular lens according to claim 1, wherein, in eachof the lenses constituting each of the cylindrical lenses, a crosssection of the lens on a second plane does not have a curvature, thesecond plane being parallel with the optical axis of the lens and beingorthogonal to a plane containing the first direction and the seconddirection.